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ITAA 1997 s118-192 · ATO MVPI · API Standards

Main Residence Exemption Apportionment Valuations.

The main residence exemption is one of the most generous concessions in the Australian tax system — and one of the most commonly miscalculated. When a property is partially rented, used for a home business, or first becomes income-producing after being your home, a valuation is required to either apportion the gain or reset the cost base to market value at the relevant date.

Reviewed by Senior Valuer, CPV (API) Updated 1 May 2026 8 min read

Key facts

Authority
ITAA 1997 s118-110 to 118-192
Trigger date
First day used to produce income
Required by
Accountants, the ATO
Who can value
Certified Practising Valuer (API)
Turnaround
5 business days standard
Fee from
$440 incl. GST (residential)

What is a main residence exemption valuation?

A main residence exemption (MRE) valuation is an independent market value report prepared as at the date a property's CGT status changes — typically the first day it is used to produce income, the date of inheritance, or the date the six-year absence rule expires. Under s118-192 of the ITAA 1997, the property is deemed to have been acquired at market value on that date, fixing a new cost base for any future sale.

"The first element of the cost base and reduced cost base of the dwelling is its market value at the time it is first used to produce income."
— ITAA 1997 s118-192(2)

The s118-192 'home first used to produce income' rule

If you start renting out a property that was previously your main residence, s118-192 ITAA 1997 deems you to have acquired it at its market value on the date it was first used to produce income. This single date can save — or cost — tens of thousands in CGT, but only if it is supported by a defensible valuation. We prepare a market valuation effective on that exact date, fully ATO-compliant and signed by a Certified Practising Valuer.

Apportionment valuations

Where a property has been partly used to produce income — for example a portion of the floor area run as a home office, a granny flat rented through Airbnb, or a duplex with one half occupied — the gain must be apportioned. We provide:

  • Floor-area apportionment with measured plans.
  • Time-based apportionment for periods of rental.
  • Combined area-and-time apportionment where both apply.
  • Documentation supporting the percentage exempt and the percentage taxable.

The six-year absence rule

Section 118-145 ITAA 1997 lets you continue to treat a former home as your main residence for up to six years while it is rented. A valuation is needed when the absence period is exceeded, when the rule is renewed by re-establishing residence, or when another CGT event occurs during the absence.

Inherited main residence

When a main residence is inherited, the beneficiary inherits a cost base of market value at the date of death (for pre-CGT properties) or the deceased's cost base (for post-CGT properties), with a two-year window in which the property can be sold fully exempt. A date-of-death valuation locks in that cost base and removes uncertainty.

MRE trigger events at a glance

The most common scenarios that require a main residence exemption valuation:

Event Section Valuation date
Home first used to produce income s118-192 Day income production began
Inherited main residence (pre-CGT) s128-15 Date of death
Six-year absence rule expires s118-145 Date the six years ended
Partial main residence (area) s118-190 Date of disposal — for apportionment
Property ceases to be MRE s118-110 et seq. Date status changed

How it works — five steps

  1. 1

    Brief & quote

    Email the property address, the relevant date, and a short note on the purpose. We return a fixed-fee quote within 2 business hours for main residence exemption valuations.

  2. 2

    Inspection

    A Certified Practising Valuer (API) attends the property for an internal and external inspection. Tenanted properties are coordinated directly with the occupier.

  3. 3

    Comparable sales analysis

    We research settled sales using RP Data, Pricefinder, APM and council records, applying the direct-comparison and (where relevant) capitalisation approaches.

  4. 4

    Report drafting

    The report is drafted to API Professional Practice Standards and the ATO Market Valuation Practice Instruction (MVPI), with full comparable schedules and signed certification.

  5. 5

    Delivery

    The signed PDF is delivered to you and (on request) directly to your accountant, solicitor or auditor within 5 business days of inspection.

Glossary

Plain-English definitions of the terms used in this report and in related ATO guidance.

Main residence exemption (MRE)
Subdivision 118-B ITAA 1997 — generally exempts a capital gain or loss on a dwelling that is the taxpayer's main residence for the entire ownership period.
Home first used to produce income
The s118-192 rule deeming a former main residence to have been acquired at market value on the day income production began.
Six-year absence rule
Section 118-145 — allows a former home to continue to be treated as a main residence for up to six years while rented, indefinitely if not rented.
Apportionment
Calculating the percentage of a capital gain that is taxable where a property has been partly used to produce income, by area and/or by time.
Two-year disposal window
Section 118-195 — an inherited main residence can be sold fully exempt within two years of death (extendable on application).
Reduced cost base
The amount used to calculate a capital loss (Division 110). Differs from the cost base in that it excludes some indexation and holding costs.

FAQs

Main residence exemption questions, answered.

The questions clients, accountants and advisers ask us most often.

Most commonly when a former home becomes a rental property (s118-192), when part of the home is used to produce income, or when an inherited main residence is sold outside the two-year exemption window. A valuation establishes the deemed acquisition cost or apportionment percentage.

No. Council rateable values are statutory site valuations — they exclude improvements and are not market value. The ATO does not accept them as substantiation for CGT positions.

It is still possible — and important — to obtain a retrospective valuation. We can value the property at the date it was first rented, even years after the event, using contemporaneous sales evidence and historical records.

Yes — at the date the rule expires or at the date of any CGT event during the absence. A valuation establishes the cost base going forward.

Generally by floor area for the income-producing portion, multiplied by the period of income production over the total ownership period. Our reports document each input clearly so the maths is transparent and reviewable.

Both are treated as partial income production. We apportion by exclusive-use area plus a share of common areas, and by the days the space was actually available for rent.

Where a deduction was claimed for occupancy expenses, yes — that triggers partial loss of the exemption. Where only running expenses (electricity, internet) were claimed, no valuation is required.

Standard residential MRE valuations start at $440 incl. GST. Apportionment workings and floor-area measurement are included in the fee.

The ATO can review any valuation. Our reports are prepared to MVPI standard so each input — date, methodology, comparables, adjustments — is documented and defensible.

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Fixed fees, 5-day standard turnaround, ATO-compliant cost-base resets and apportionments.

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